From c8cdd2be213f0f5372287a764225665f1ac64e56 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Fri, 20 May 2016 17:04:27 -0700
Subject: [PATCH] init/main.c: simplify initcall_blacklisted()
Using kasprintf to get the function name makes us look up the name
twice, along with all the vsnprintf overhead of parsing the format
string etc. It also means there is an allocation failure case to deal
with. Since symbol_string in vsprintf.c would anyway allocate an array
of size KSYM_SYMBOL_LEN on the stack, that might as well be done up
here.
Moreover, since this is a debug feature and the blacklisted_initcalls
list is usually empty, we might as well test that and thus avoid looking
up the symbol name even once in the common case.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
init/main.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/init/main.c b/init/main.c
index fa9b2bdde183..bc0f9e0bcf22 100644
--- a/init/main.c
+++ b/init/main.c
@@ -706,21 +706,20 @@ static int __init initcall_blacklist(char *str)
static bool __init_or_module initcall_blacklisted(initcall_t fn)
{
struct blacklist_entry *entry;
- char *fn_name;
+ char fn_name[KSYM_SYMBOL_LEN];
- fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
- if (!fn_name)
+ if (list_empty(&blacklisted_initcalls))
return false;
+ sprint_symbol_no_offset(fn_name, (unsigned long)fn);
+
list_for_each_entry(entry, &blacklisted_initcalls, next) {
if (!strcmp(fn_name, entry->buf)) {
pr_debug("initcall %s blacklisted\n", fn_name);
- kfree(fn_name);
return true;
}
}
- kfree(fn_name);
return false;
}
#else
--
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